1. Field of the Invention
The invention relates to an injection structure in accordance with a fiber-composite semifinished product for manufacturing a fiber-composite component, having a gate device for feeding matrix material, a distribution fabric, and a barrier layer that is impermeable to the matrix material and a method for producing fiber-reinforced plastic components.
2. Discussion of Background Information
In the manufacture of fiber-composite components, hereinafter called FC components, using resin injection methods, pores may be formed as a result of gas bubbles, dissolved gases, and other volatile constituents contained in the matrix material. As a result, the quality of the components is reduced, to the point of unusability.
Described in German patent DE 100 13 409 C1 is a device and a process for manufacturing fiber-reinforced plastic components from dry fiber-composite semifinished products using an injection method for injecting matrix material with a gas-permeable and matrix-material-impermeable membrane, which is arranged around the semifinished product on at least one side and forms a first space and into which matrix material can be introduced, having a flow promoter arranged on a surface of the semifinished product, having a second space, sealed with respect to a tool, adjacent to the first space, which is delimited from the surroundings by a gas-impermeable and matrix-material-impermeable film. Air is removed from the second space by suction, matrix material is drawn from the reservoir into the evacuated first space and the flow promoter causes distribution of the matrix material over the surface of the semifinished product facing it and penetration thereof vertically into the semifinished product.
In this process, the matrix material is distributed by a flow promoter over the fiber-composite semifinished product, and from there penetrates the semifinished product. The flow promoter is delimited on one side by the gas-permeable and matrix-material-impermeable membrane. During transport of the matrix material in the thin flow promoter, degassing of the matrix material takes place. The degassing takes place through the membrane adjoining the flow promoter into the evacuated second chamber. For efficacious degassing, it is necessary for the matrix material to first be able to travel an adequately long distance through the flow promoter before it enters the semifinished product.
In the commonly used gate arrangements for introducing the matrix material into the flow promoter, such film degassing does not occur directly beneath the gates, and occurs only incompletely in the areas directly adjacent thereto. Accordingly, the probability is greater beneath the gates and in the areas adjacent thereto that pore formation will take place.
Another disadvantage of this process resides in that the use of two chambers which requires greater expenditure of auxiliary materials for the membrane as compared to the single-chamber principle likewise known in fiber composite technology.
In addition, degassing of the matrix material can take place according to a method known from the general prior art wherein the matrix material is remelted into a thin layer (film) in an evacuated space. In general, the thinner the matrix material layer to be degassed, the more effective such a degassing process. This process for degassing the matrix material, which is also called film degassing, has the following disadvantages. For example, the additional degassing step is unfavorable with regard to costs and additional inputs; the matrix material must be heated for the degassing step that causes aging processes to occur; the matrix material can again absorb volatile constituents such as water vapor from the air, prior to later processing to produce fiber-composite components; and the matrix material can react with auxiliary materials during the course of the injection process, with the formation of gas. Thus, reactions with low-cost, flexible silicone profiles for gates have been observed.